Phase-Transition-Driven Regional Distribution of Rare-Earth …

Phase transition of the polymorphs is critical for controlled synthesis and property modulation of functional materials. Upconversion emissions from an efficient hexagonal sodium rare-earth (RE) fluoride compound, β-NaREF 4, which is generally obtained from the phase transition of the cubic (α-) phase counterpart, are attractive for …

Rare earth element distribution and mineralization in …

Highlights We present rare earth element distribution in soils over Sweden. La, Ce and Nd are the most abundant REEs in soils. PCA were applied to study structure and spatial distribution of REE. Color composites of PC maps produced from the soils dataset reflect bedrock lithology. There is enrichment of the LREEs in the Archean …

Transport and distribution of residual nitrogen in ion-adsorption rare

Nitrogen transport and distribution in rare earth tailing were examined. • A low NH 4 +-N in leaching liquid but high level NH 4 +-N in soils was observed. • NH 4 +-N and NO 3 −-N increased with depth but nitrogen is dominated by NH 4 +-N. • NH 4 +-N a positive correlating to NO 3 −-N declined from the knap to piedmont.

Rare earth element distribution in the Atlantic sector of the …

1. Introduction. The isotopic composition of the rare earth element Nd in seawater is a GEOTRACES key parameter because it is frequently applied as a chemical tracer of present and past ocean circulation (e.g., Piepgras and Wasserburg, 1980, Frank, 2002, Piotrowski et al., 2005, Pena and Goldstein, 2014).It is clear that the source of rare …

Adsorption of rare earth elements in regolith-hosted clay …

Fig. 1: Global distribution of rare earth element deposits. Regolith-hosted ion-adsorption-type REE deposits (shown in white circles) dominantly occur in the tropics …

Processes controlling Rare Earth Element distribution in …

In phosphorites, the content and distribution of rare earth elements are linked to the environment of phosphogenesis. This paper focuses on the question of sources and processes controlling the rare earth element content of apatite from Belgian phosphorites formed during three major phosphogenic events in the Lower Palaeozoic, …

Variation of the distribution coefficients of rare earth …

Rare earth element (REE) concentrations in the carbonate lattice of four species of coral have been analyzed and compared with the dissolved REE in ambient seawaters. ... Rare-earth element distribution in Holocene and Pleistocene coral and their redistribution during diagenesis. Chem. Geol, 28 (1980), pp. 279-289. View PDF View …

Rare earth elements in the upland soils of northern China: …

1. Introduction. Rare earth elements (REEs) include 15 lanthanide elements, from lanthanum to lutetium, scandium, and yttrium (Mihajlovic and Rinklebe, 2018).REEs share similar physicochemical properties and usually exist together in environmental matrices rather than in isolation (Li et al., 2013; Godwyn-Paulson et al., 2022).REEs are …

Rare Earths Reserves: Top 8 Countries

7. United States. Reserves: 2.3 million MT. While the US reported the second highest output of rare earths in 2022 at 43,000 MT, the country takes the sixth top spot in terms of global rare earths ...

Distribution, source and contamination of rare earth …

1. Introduction. Rare earth elements (REEs: La–Lu) are a group of chemically similar elements that are industrially important due to their use in modern commodities such as high technology, agricultural fertilization, medical techniques and also widely used as tracers in geoscience (Adeel et al., 2019; Shajib et al., 2020).They have been used to …

Rare Earth Element Distribution in Fly Ash …

PDF | On Jan 1, 2017, Madison M. Hood and others published Rare Earth Element Distribution in Fly Ash Derived from the Fire Clay Coal, Kentucky | Find, read and cite all the research you need on ...

USGS Mineral Resources On-Line Spatial Data

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Frontiers | Rare Earth Element Distribution in the NE …

Seawater rare earth element (REE) concentrations are increasingly applied to reconstruct water mass histories by exploiting relative changes in the distinctive normalised patterns. However, the mechanisms by which water masses gain their patterns are yet to be fully explained. To examine this, we collected water samples along the …

RARE EARTHS1

The estimated value of rare-earth compounds and metals imported by the United States in 2020 was $110 million, a significant decrease from $160 million in 2019. The estimated distribution of rare earths by end use was as follows: catalysts, 75%; ceramics and glass, 6%; polishing, 5%; metallurgical applications and alloys, 4%; and other, 10%.

The Principal Rare Earth Elements Deposits of the …

The Principal Rare Earth Elements Deposits of the. United States—A Summary of Domestic Deposits and a Global Perspective. Sm Gd Pr La Nd Ce. Cover photo: Powders of six rare earth elements oxides. Photograph by Peggy Greb, Agricultural Research Center of ... Typical rare earth elements distribution in Bear Lodge Mountains deposit, …

Distribution of Rare Earth Elements and Yttrium in …

Deep-sea sediments enriched in rare earth elements and yttrium (REY) are attracting scientific and exploration attention as a new REY resource. In the Clarion-Clipperton Fracture Zone (CCFZ) of the northeastern Pacific, sedimentary units with high REY contents (average REY content >700 ppm) occur sporadically at only a few …

Rare Earth Elements (REE): Why are they …

What is a Rare Earth Element (REE)? Rare earth elements (REE) are a group of seventeen chemical elements that occur together in the periodic table, 15 lanthanides (Z=57 through 71), Scandium, and …

Rare Earth Elements: Where in the World Are They?

The 17 rare earth elements are: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), …

Rare-earth element

Bastnasite, a fluorocarbonate, is the principal source of rare earths. About 94 percent of the rare earths used in the world come from mines in Mountain Pass, California, U.S.; …

Global rare earth elements projects: New developments and …

Rare earth metals refer to a group of 17 chemical elements including 15 lanthanides with the addition of scandium (Sc) and yttrium (Y), as defined by the International Union of Pure and Applied Chemistry. ... Distribution features of current global REE projects. A surging demand for rare earth metals (especially Pr, Nd, Tb, Dy) …

Rare earth element distribution in Caribbean seawater: Continental

The rare earth element (REE) concentrations of full water column profiles from ten stations in the Caribbean, the Gulf of Mexico, and the Florida Straits, as well as of surface waters close to the mouth of the Orinoco River have been analyzed. ... The Distribution of Rare Earth Elements in the Ocean: A Compilation of Seawater …

Average distribution of rare earth elements in each deposit …

Distribution of rare earth elements in various mines is shown in Figure 1. REEs are also often found associated with uranium/thorium mineralization and uranium ores often contain appreciable REE ...

Rare earth element distribution in lavas and ultramafic …

Lavas and included xenoliths from the Comores Archipelago have been analysed for the rare earth elements (REE) La-Lu. Among basaltic lava types fractionation of REE rock/chondrite distribution patterns is more extreme with greater SiO 2 undersaturation and contents of incompatible elements. Enrichment and slight fractionation of REE in the …

Rare-earth element

Rare-earth element - Abundance, Occurrence, Reserves: As noted above, the rare earths are fairly abundant, but their availability is somewhat limited, primarily because their concentration levels in many ores are quite low (less than 5 percent by weight). An economically viable source should contain more than 5 percent rare earths, unless they …

The Geopolitics of Rare Earth Elements

The rare earth elements are already critical to the U.S. defense sector, but rare earth mining, processing and fabrication capabilities will even more strongly influence geopolitical dynamics in the coming years as the world undergoes its nascent energy transition and transportation evolution.In the near term, China will benefit from its near …

Distribution, mode of occurrence, and significance of rare-earth …

In addition to economic importance, the distribution of rare-earth elements along with trace elements and mineralogical characterization has been provided important information about the provenance, mode of occurrence, and paleodepositional setting of the concern basin (Dai et al. 2016a, 2018; Wang et al. 2022).

Rare earth elements distribution and geochemical behaviour in …

The distribution of rare earth elements in groundwaters: assessing the role of source-rock composition, redox changes and colloidal particles. Geochim. Cosmochim. Acta, 64 (24) (2000), pp. 4131-4151, 10.1016/S0016-7037(00)00494-4. View PDF View article View in Scopus Google Scholar.

Redistribution and chemical speciation of rare earth …

1. Introduction. Rare earth elements (REEs) comprise a group of 17 metallic elements including 15 lanthanides, scandium and yttrium. However, Sc is excluded from REEs due to its small ionic radius, and promethium is rarely present in the natural environment (<600 g in the Earth' s crust) (IUPAC, 2005; Migaszewski and Gałuszka, …